Noncaking particulate detergent



Sept. 7, 1954 7 BY WEIGHT CAKED w. T. BAILEY 2,688,599

NONCAKING PARTICULATE DETERGENT COMPOSITION Filed March 50, 1951 I I I I 90 CAKING OF DETERGENT COMPOSITIONS CONTAINING sODIuM SILICATES OF 80 DIFFERENT NA2O=sIO2 MOL RATIO AFTER 3 DAYS EXPOSURE AT 90F AND 80% RELATIVE HUMIDITY. 7o

NA O SIO MOL RATIO OF SODIUM SILICATE F'IOI INVENTOR WESLEY 7'. BA/LEV ELM AT TORN EYS Patented Sept. 7, 1954 UNITED STATES ATENT OF NONCAKING PARTICULATE DETERGENT COMPOSITION Application March 30, 1951, Serial No. 218,481

8 Claims.

This invention relates to improved synthetic alkyl aryl sulfonate detergents. More particularly, it relates to detergent compositions stabilized against caking in storage and containing as the active organic detergent ingredient a longchain monoalkyl benzene sulfonate.

In the total picture of synthetic detergents presently available on the market, the anionic alkyl aryl sulfonates occupy by far the most important place. Among the detergent compositions based on these anionic sulfonates, those containing sodium polypropylene phenyl sulfomate with 9 to 18 carbon atoms, and preferably with 12 to 15 carbon atoms, in the polypropylene chain are especially efiective for detergency purposes, and represent, therefore, a sizeable segment of the alkyl aryl sulfonate detergent market. The techniques employed for the preparation of these sodium polypropylene phenyl sulfonates are at the present time more or less wellestablished in the art, one of the particularly efficient methods having been disclosed in detail in U. S. Patent No. 2,477,383 to A. H. Lewis. As a general rule, detergent compositions containing sodium polypropylene phenyl sulfonate as the effective organic detergent ingredient also contain inorganic builders, most frequently sodium sulfate, either formed during the neutralization of the mixture of polypropylene phenyl sulfonic acid and unreacted sulfuric acid, or added subsequently to the neutralized sulfonate slurry prior to the drying and reduction thereof to the desirable solid, particulate form and size. Other builders such as common sodium silicates and various sodium-containing phosphates can also be added to these compositions in the form of sodium salts, e..g., tetrasodium pyrophosphate or sodium tripolyphosphate. Furthermore, an organic additive or extender such as sodium carboxymethyl cellulose, may be incorporated into the detergent compositions to enhance the detergency of sodium polypropylene phenyl sulfonate. After bringing together all of these ingredients in the amounts required by a particular formulation, the resulting slurry is dried and converted by any suitable, method, for instance by spraydrying, to the solid form, e. g., flakes, chips, granules or beads. The resulting particulate product is then sold to the user packaged in containers such .as cartons, wooden boxes or glass jars.

Particularly efficient detergent compositions available in the form of solid particles contain from 30 to 40% by weight of sodium C12-C15 polypropylene phenyl sulfonate, from 10 to 30% by wei ht of sodium sulfate, from 40 to 60% by weight of sodium tripolyphosphate, and from to 3 by weight of sodium carboxymethyl cellu- 2. lose, based on the total weight of the solids in the mixture.

However, these last mentioned, otherwise highly satisfactory formulations possess one serious drawback, namely, they tend to cake upon prolonged storage, particularly in moist atmosphere, even though the container be tightly closed. The consequences of this tendency to cake are: (1) Unsatisfactory flow from the package, particularly from conventional small-size cardboard boxes; (2) presence of lumps which are difiioult to dissolve in water; and, finally, (3) production ofirritating dust upon shaking the package in order to crumble these lumps and to facilitate the flow of the detergent material from the package.

I have now found that this caking tendency can be substantially reduced, if not completely obviated, by incorporating into the detergent composition from 3 to 5%, based on the weight of the whole water-free composition, of a particular kind of sodium silicate. This sodium silicate additive is the water-soluble sodium silicate characterized by a sodium oxide to silica (Na2O-:SiOz) mol ratio greater than about 0.62, and preferably comprised in the range of values greater than 1.0 and as high as 1.5. These latter preferred sodium silicates with the aforeindicated critical sodium oxide to silica mol ratio greater than 1.0 are represented, for instance, by granular water-soluble silicates: manufactured and sold on the market under the trade-names of Metso Granular and Metso 99, by the Philadelphia Quartz Company of Philadelphia, Pa. The introduction of sodium silicates having a sodium oxide to silica mol ratio greater than about 0.62 and as high as about 1.5 into the detergent composition, in accordance with my invention, is efiected in a very simple and straightforward manner. Sodium silicate is added to the aqueous slurry or solution of sodium alkyl benzene sulfonate, sodium sulfate, and sodium tripolyphosphate (at a concentration of about 30 to solids), whereupon the slurry is dried in the desired conventional manner to yield solid detergent particles.

When a detergent composition, a sample of which caked to as much as 79% after remaining stored for 3 days, received an addition of from 3 to 5% by weight of the sodium, silicate additive with a sodium oxide to silica mol ratio greater than 0.62 and as high as 1.5, and was then left stored in the container for the same period of time, it was observed upon re-opening the containers that in the case of samples containing sodium silicate with a mol ratio on the order of 0.62, the extent of caking was only 10 to 12% by weight, while in the case of sodium silicates with the sodium oxide to silica mol ratio above 1.0, the caking amounted to a mere 4 to 5% by weight on the average. This is entirely unexpected, for similar detergent compositions containing commonly 'used sodium silicates possessing sodium oxide to silica mol ratios of less than about 0.5, cake very badly, as will be seen from the illustrative data appearing hereinafter.

A large number of test runs have been effected to compare the extent of caking in the detergent compositions containing no sodium silicate, or containing sodium silicates, with a different Na2O:SiOz mole ratio, with the extent of caking in the detergent compositions containing therein in accordance with the invention from 3 to 5% by weight of sodium silicate characterized by a NazOzsioz mole ratio above about 0.62 and as high as 1.5.

The extent of caking was determined by the following method: Weighed samples of the dry particulate detergent compositions were placed in small untreated sealed cardboard boxes (l x 2 x 4"). Three samples of each composition were used in each separate test. These samples were introduced into a humidity cabinet and placed therein in a completely random manner, exposed to a relative humidity of about 80% at a temperature of about 90 F. for three days. At the end of this exposure, all samples were reweighed and the extent of caking was determined by cutting away the side of each cardboard box and carefully transferring the sample onto a No. 4 sieve /4" mesh) from a minimum height. This sieve was gently swirled until all particles came into contact with the screen. The material which did not pass through the screen in this treatment was considered to be caked. The results of these tests clearly show the unexpected and remarkable reduction of the caking tendency due to the introduction of the sodium silicate characterized by a sodium oxide to silica ratio from about 0.62 to about 1.5, and particularly from above about 1.0 to about 1.5.

Table I below offers the results of several representative tests, obtained on a drum-dried detergent composition which contained 37% of sodium C12-C15 polypropylene phenyl sulfonate, 16% of sodium sulfate, 42% of sodium tripolyphosphate,

1% sodium carboxymethyl cellulose and 4% of sodium silicate (in per cent by weight on dry basis). This composition, when dissolved in a 0.5% concentration in water, indicated a pH from about 9.0 to about 9.5 at 0., depending on the nature of sodium silicate contained there- TABLE I Caki'ng observed after 3 days at 90 F. and

In addition, the drawing in Figure 1 shows the curve obtained on the basis of the test data in Table I by plotting the percentage of the material caked as a function of the sodium oxide to silica mole ratio. Both the test data in the table and the curve in the drawing show beyond all doubt that the caking of the particulate detergent compositions containing from 30 to 40% by weight of sodium C12-C15 polypropylene phenyl sulfonate, from 10% to 30% by weight of sodium sulfate, from 40% to 60% by weight of sodium tripolyphosphate and from 0 to 3 by weight of sodium carboxymethyl cellulose, and additionally containing water-soluble sodium silicates characterized by a sodium oxide to silica ratio from 0.62 to 1.5 in an amount from 3 to 5% by weight, based on the total solid ingredients of the detergent mixture, is remarkablyreduced by the addition of such sodium silicates. It is noted from the curve that the presence of sodium silicates having different NazOZSiOz mole ratios, such as are commonly used in the art as builders for alkyl benzene sulfonate detergent compositions, does not reduce the caking tendency of the particular combination of sodium sulfonate, sodium silicate. tripolyphosphate and sodium carboxymethyl cellulose, with which this invention is concerned.

The effective organic detergent ingredient of alkyl benzene sulfonate detergent compositions which may be stabilized against caking in accordance with my invention can be also prepared by alkylating benzene with a chlorinated kerosene fraction containing from 9 to 18 and preferably from 12 to 15 carbon atoms in the alkyl chain, and by treating the resulting Keryl benzene with a suitable sulfonating agent'tosecure a sulfonic-sulfuric acid mixture convertible to the corresponding sulfonate and sulfate by appropriate neutralization techniques. In fact, any C9C1a and preferably C12 to C15 monoalkyl benzene stock with little or no branching of the alkyl chain may be employed to prepare (by sulfonation and neutralization), the alkyl benzene sulfonate detergent ingredient for the detergent compositions stabilized against caking in accordance with my invention.

Sodium alkyl benzene sulfonate and sodium sulfate of alkyl benzene sulfonate detergent compositions which may be improved by addition of 3 to 5% by weight of the particular sodium silicate in accordance with my invention may be replaced by magnesium alkyl benzene sulfonate and magnesium sulfate without affecting the anticaking effect of the sodium silicate addition. In such a case, when neutralizing the mixture of alkyl benzene sulfonic and unreacted sulfuric acid obtained by sulfonation of an alkyl benzene stock, slurries of magnesium alkaline compounds, e. g., MgO or Mg(OI-I) 2 are employed.

It is to be understood that the results of the particular representative series of test runs in Table I and the description offered hereinbefore are merely illustrative of the invention and do not limit it, except as set forth in the appended claims.

I claim:

1. A non-caking, free-flowing solid particulate detergent composition consisting essentially of from 30 to 40 parts by weight of sodium (312-015 polypropylene phenyl sulfonate, from 10 to 30 parts by weight of sodium sulfate, from 40 to 60 parts by weight of sodium tripolyphosphate, said parts by weight of sulfonate, sulfate and tripolyphosphate adding up to a total of parts by weight, said detergent composition further containing from 3 to 5% by weight, based on the aggregate weight of said sulfonate, sulfate and tripolyphosphate, of sodium silicate in which the mole ratio of sodium oxide to silica ranges from above about 0.62 to as high as about 1.5.

2. A non-caking, free-flowing solid particulate detergent composition consisting essentially of from 30 to 40 parts by weight of sodium ClZ-C15 polypropylene phenyl sulfonate, from to 30 parts by weight of sodium sulfate, from 40 to 60 parts by weight of sodium tripolyphosphate, said parts by weight of sulfonate, sulfate and tripolyphosphate adding up to a total of 100 parts by weight, said detergent composition further containing from 3 to 5% by weight, based on the aggregate weight of said sulfonate, sulfate and tripolyphosphate, of sodium silicate in which the mole ratio of sodium oxide to silica ranges from above about 1.0 to as high as about 1.5.

3. A non-caking, free-flowing detergent composition consisting essentially of from 30 to 40 parts by weight of sodium 012-(315 polypropylene phenyl sulfonate, from 10 to 30 parts by weight of sodium sulfate, from 40 to 60 parts by weight of sodium tripolyphosphate, said parts by weight of sulfonate, sulfate and tripolyphosphate adding up to a total of 100 parts by weight, said detergent composition further containing from 1 to 3% by weight of sodium carboxymethyl cellulose, and from 3 to 5 by weight of sodium silicate in which the mole ratio of sodium oxide to silica is in the range from above about 0.62 to as high as about 1.5, based on the aggregate weight of said sulfonate, sulfate and tripolyphosphate.

4. A non-caking, free-flowing detergent composition consisting essentially of from 30 to 40 parts by weight of sodium C12-C15 polypropylene phenyl sulfonate, from 10 to 30 parts by weight of sodium sulfate, from 40 to 60 parts by weight of sodium tripolyphosphate, said parts by weight of sulfonate, sulfate and tripolyphosphate adding up to a total of 100 parts by weight, said detergent composition further containing from 1 to 3% by weight of sodium carboxymethyl cellulose, and from 3 to 5% by weight of sodium silicate in which the mole ratio of sodium oxide to silica is in the range from above about 1.0 to. as high as about 1.5, based on the aggregate weight of said sulfonate, sulfate and tripolyphosphate.

5. A non-caking, free-flowing solid particulate detergent composition consisting essentially of from 30 to 40 parts by weight of an organic 012-015 alkyl benzene sulfonate salt from the group consisting of sodium 012-015 alkyl benzene sulfonate and magnesium C12-C15 alkyl benzene sulfonate, from 10 to 30 parts by weight of an inorganic sulfate from the group consisting of sodium sulfate and magnesium sulfate, from 40 to 60 parts by weight of sodium tripolyphosphate, said parts by weight of sulfonate, sulfate and tripolyphosphate adding up to a. total of 100 parts by weight, said detergent composition further containing from 3 to 5% by weight, based on the aggregate weight of said sulfonate, sulfate and tripolyphosphate of sodium silicate in which the mole ratio of sodium oxide to silica ranges from above 0.62 to as high as about 15.

6. A non-caking, free-flowing solid particulate detergent composition consisting essentially of from 30-40 parts by Weight of a sodium ClZ-Cl5 alkyl benzene sulfonate, from 10-30 parts by weight of sodium sulfate, from 40-60 parts by weight of an inorganic phosphate builder selected from the group consisting of sodium tripolyphosphate and tetrasodium pyrophosphate, said parts by weight of sulfonate, sulfate and tripolyphosphate adding up to a total of parts by weight, said detergent composition further containing from 3-5% by weight, based on the aggregate weight of said sulfonate, sulfate and tripolyphosphate, of sodium silicate in which the mole ratio of sodium oxide to silica ranges from above about 0.62 to about 1.5.

7. A non-caking, free-flowing solid particulate detergent composition consisting essentially of from 30-40 parts by weight of sodium C12-C15 polypropylene phenyl sulfonate, from 10-30 parts by weight of sodium sulfate, from 40-60 parts by weight of an inorganic phosphate builder selected from the group consisting of sodium tripolyphosphate and tetrasodium pyrophosphate, said parts by weight of sulfonate, sulfate and tripolyphosphate adding up to a total of 100 parts by weight, said detergent composition further containing from 3-5% by weight, based on the aggregate weight of said sulfonate, sulfate and tripolyphosphate, of sodium silicate in which the mole ratio of sodium oxide to silica ranges from above about 0.62 to about 1.5.

8. A non-caking, free-flowing detergent composition consisting essentially of 30 to 40 parts by weight of sodium polypropylene benzene sulfonate containing 12 to 15 carbon atoms in the polypropylene chain, from 10 to 30 parts by weight of an inorganic sulfate of the group consisting of sodium sulfate and magnesium sulfate, and from 40 to 60 parts by weight of an inorganic phosphate builder of the group consisting of sodium tripolyphosphate and tetrasodium pyrophosphate, said parts by weight of sulfonate, inorganic sulfate and inorganic phosphate adding up to a total of 100 parts by weight, said detergent composition further containing from 3 to 5% by weight of sodium silicate in which the mole ratio of sodium oxide to silica is in the range from about 0.62 to about 1.5.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,477,383 Lewis July 26, 1949 2,515,577 Waldeck July 18, 1950 

8. A NON-CAKING, FREE-FLOWING DETERGENT COMPOSITION CONSISTING ESSENTIALLY OF 30 TO 40 PARTS BY WEIGHT OF SODIUM POLYPROPYLENE BENZENE SULFONATE CONTAINING 12 TO 15 CARBON ATOMS IN THE POLYROPYLENE CHAIN, FROM 10 TO 30 PARTS BY WEIGHT OF AN INORGANIC SULFATE OF THE GROUP CONSISTING OF SODIUM SULFATE AND MAGNESIUM SULFATE, AND FROM 40 TO 60 PARTS BY WEIGHT OF AN INORGANIC PHOSPHATE BUILDER OF THE GROUP CONSISTING OF SODIUM TRIPOLYPHOSPHATE AND TETRASODIUM PYROPHOSPHATE, SAID PARTS BY WEIGHT OF SULFONATE, INORGANIC SULFATE AND INORGANIC PHOSPHATE ADDING UP TO A TOTAL OF 100 PARTS BY WEIGHT, SAID DETERGENT COMPOSITION FURTHER CONTAINING FROM 3 TO 5% OF WEIGHT OF SODIUM SILICATE IS IN THE THE MOLE RATIO OF SODIUM OXIDE TO SILICA IS IN THE RANGE FROM ABOUT 0.62 TO ABOUT 1.5. 